1. Field of the Invention
The invention relates in general to a touch detection method and an associated apparatus, and more particularly, to a touch detection method applied when a display device displays a blanking interval and an associated apparatus.
2. Description of the Related Art
In a display architecture of a liquid-crystal display (LCD) panel, gate drivers and source drivers are controlled by timing signals generated by a timing controller to drive a frame and thus complete display of an entire frame. A source driver provides data to be displayed by pixels, i.e., provides voltage signals corresponding to different grayscales. A gate driver, in a unit of rows, controls a plurality of pixels at the same row to simultaneously receive the data provided by the source driver. More specifically, the timing controller controls the source driver to sequentially convert data to be displayed by pixels at a 1st row, a 2nd row, a 3rd row . . . an Nth row of a frame to corresponding voltage signals at an output end of the source driver, and controls the gate driver to have the pixels at the 1st, the 2nd, the 3rd and the Nth row of a frame receive the voltage signals respectively outputted by the source driver.
When a display device is equipped with a touch function, in the prior art, a touch detection circuit usually performs functions such as data access, computations and transmission of touch point information while the display device displays a vertical blanking interval. In a blanking interval, source drivers and gate drivers do not at all update data of any pixel, and thus noise interference on a panel during such blanking interval is minimal. A vertical blanking interval is the time difference between the end of the display of one frame and the beginning of the display of a next frame. Further, a horizontal blanking interval is the time difference between pixels of one row stop receiving data provided by a source driver and pixels of a next row start receiving data provided by the source driver.
Compared to the vertical blanking interval, the horizontal blanking interval is too short to carry out a complete touch detection procedure, and so the horizontal blanking interval is not conventionally adopted for touch detection. Although the vertical blanking interval is sufficient for carrying out a complete touch detection procedure, it is only available between having updated one frame and starting to update a next frame. Within the vertical blanking interval, a touch detection circuit is required to perform the above functions of data access, computations and transmission of touch point information, meaning that the number of times and timings for touch detection are limited. For example, within one frame period, the prior art can only perform one touch detection procedure after having updated one frame. Therefore, there is a need for a solution for improving the above limitation.